U.S. patent application number 12/107465 was filed with the patent office on 2008-10-23 for intraluminary stent relocating apparatus.
This patent application is currently assigned to BOSTON SCIENTIFIC SCIMED, INC.. Invention is credited to Gary A. Jordan, Mark D. Wood.
Application Number | 20080262592 12/107465 |
Document ID | / |
Family ID | 39873040 |
Filed Date | 2008-10-23 |
United States Patent
Application |
20080262592 |
Kind Code |
A1 |
Jordan; Gary A. ; et
al. |
October 23, 2008 |
INTRALUMINARY STENT RELOCATING APPARATUS
Abstract
An apparatus for moving an object disposed within a body lumen.
The apparatus includes a first sheath, a coupling member and at
least one contraction member for engaging at least a portion of the
object. The coupling member is movable relative to the first sheath
between a retracted position and a capture position. In the
retracted position, a distal portion of the coupling member is
disposed within the first sheath. In the capture position, the
coupling member distal portion is disposed outside the first
sheath. The coupling member is also selectively attachable to the
object in at least the capture position. When the coupling member
is attached to the object and the contraction member is directly
engaged with the object, a predetermined coupling member movement
relative to the contraction member radially contracts at least a
portion of the object thereby facilitating movement of the object
within the body lumen.
Inventors: |
Jordan; Gary A.;
(Litchfield, NH) ; Wood; Mark D.; (Shrewsbury,
MA) |
Correspondence
Address: |
HOFFMANN & BARON, LLP
6900 JERICHO TURNPIKE
SYOSSET
NY
11791
US
|
Assignee: |
BOSTON SCIENTIFIC SCIMED,
INC.
Maple Grove
MN
|
Family ID: |
39873040 |
Appl. No.: |
12/107465 |
Filed: |
April 22, 2008 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60913420 |
Apr 23, 2007 |
|
|
|
Current U.S.
Class: |
623/1.11 |
Current CPC
Class: |
A61F 2002/9528 20130101;
A61F 2002/9511 20130101; A61F 2002/9534 20130101; A61F 2/95
20130101 |
Class at
Publication: |
623/1.11 |
International
Class: |
A61F 2/84 20060101
A61F002/84 |
Claims
1. An apparatus for moving an object disposed within a body lumen,
the apparatus comprising: a first sheath for insertion into the
body lumen; a coupling member movable relative to the first sheath
between a retracted position wherein a distal portion of the
coupling member is disposed within the first sheath and a capture
position wherein the coupling member distal portion is disposed
outside the first sheath, the coupling member selectively
attachable to the object in at least the capture position; and at
least one contraction member for engaging at least a portion of the
object, whereby when the coupling member is attached to the object
and the contraction member is directly engaged with the object then
a predetermined coupling member movement relative to the
contraction member radially contracts at least a portion of the
object thereby facilitating movement of the object within the body
lumen.
2. The apparatus of claim 1, wherein the coupling member and the
contraction member cooperate to draw the object at least partially
within the first sheath.
3. The apparatus of claim 1, wherein the coupling member includes
at least one first grasping member for removeably attaching to the
object, wherein the first grasping member includes at least one of
a hook, forceps, clamp and snare.
4. The apparatus of claim 1, wherein the contraction member
includes a deployable funnel with an inner passage for receiving
the object, at least one portion of the funnel being selectively
adjustable between a radially compressed and a radially expanded
configuration.
5. The apparatus of claim 4, wherein another predetermined coupling
member movement relative to the funnel encourages the funnel to
adjust to the expanded configuration.
6. The apparatus of claim 4, wherein the coupling member is axially
moveable relative to the funnel.
7. The apparatus of claim 4, wherein the funnel is axially moveable
relative to the first sheath.
8. The apparatus of claim 4, wherein at least a distal portion of
the coupling member is disposed within the inner passage when the
coupling member is in the retracted position.
9. The apparatus of claim 4, wherein the coupling member includes
at least one stop member for limiting axial movement of the
coupling member relative to the funnel.
10. The apparatus of claim 4, wherein the coupling member includes
a cap, whereby the cap selectively retains the funnel in the
compressed configuration.
11. The apparatus of claim 4, wherein the funnel is disposed at a
distal end of the first sheath.
12. The apparatus of claim 4, wherein the funnel is integrally
formed with the first sheath.
13. The apparatus of claim 1, wherein the contraction member
includes a second sheath moveably disposed with respect to the
first sheath, wherein at least a portion of the second sheath is
coaxially disposed within the first sheath.
14. The apparatus of claim 3, wherein the coupling member includes
at least one elongate rod extending generally parallel to the first
sheath.
15. The apparatus of claim 14, wherein the first grasping member is
disposed on a distal end of the rod.
16. The apparatus of claim 15, wherein at least a portion of the
rod is biased to diverge radially away from a central longitudinal
axis of the sheath.
17. The apparatus of claim 13, wherein at least one elongate rod
extends from a distal end of the second sheath, the rod extending
generally parallel to at least one of the first and second sheath,
wherein at least a distal portion of the rod is disposed outside
the first sheath when the contraction member is in the capture
position.
18. The apparatus of claim 3, wherein the contraction member
includes at least one second grasping member for removeably
attaching to the object, whereby the first and second grasping
members cooperate to radially contract the object.
19. The apparatus of claim 18, wherein when in the capture position
the first grasping member secures to a distal portion of the object
and the second grasping member secures to a proximal portion of the
object.
20. A method for moving an intraluminary object disposed within a
body, comprising: providing a first sheath for insertion into a
body lumen; providing a coupling member movable relative to the
first sheath between a retracted position wherein a distal portion
of the coupling member is disposed within the first sheath and a
capture position wherein the coupling member distal portion is
disposed outside the first sheath, the coupling member selectively
attachable to the object in at least the capture position; and
providing at least one contraction member for engaging at least a
portion of the object, whereby when the coupling member is attached
to the object a predetermined coupling member movement relative to
the contraction member radially contracts at least a portion of the
object thereby facilitating movement of the object within the body
lumen.
21. The method according to claim 20, wherein the contraction
member includes a deployable funnel with an inner passage for
receiving the object, at least one portion of the funnel being
selectively adjustable between a radially compressed and a radially
expanded configuration.
22. The method according to claim 21, further comprising: inserting
the first sheath, the coupling member and the contraction member
into the body lumen with at least the coupling member in a
retracted position; moving the coupling member into the capture
position; and attaching the coupling member to the object.
23. The method according to claim 22, further comprising:
initiating the predetermined coupling member movement and moving
the object relative to the body lumen.
24. The method according to claim 20, wherein the coupling member
includes at least one grasping member for removeably attaching to
the object, wherein the grasping member includes at least one of a
hook, forceps, clamp and snare.
25. The method according to claim 20, wherein the contraction
member includes a second sheath moveably disposed with respect to
the first sheath, wherein at least a portion of the second sheath
is coaxially disposed within the first sheath.
26. The method according to claim 25, wherein the coupling member
includes at least one elongate rod extending generally parallel to
the first sheath.
27. The method according to claim 26, wherein the grasping member
is disposed on a distal end of the rod.
28. The method according to claim 20, wherein the predetermined
coupling member movement includes a distal portion of the coupling
member moving at least one of toward and away from a distal portion
of the contraction member.
29. The method according to claim 20, wherein the radial
contraction of the object is associated with an elongation of the
object.
30. The method according to claim 20, wherein the radial
contraction of the object is performed by the object moving through
the contraction member.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application Ser. No. 60/913,420 filed on Apr. 23, 2007.
FIELD OF THE INVENTION
[0002] This invention relates to a method and system for treatment
of body lumens with stents and other prostheses, and more
particularly to an apparatus, system and method for retrieving,
adjusting and/or repositioning an intraluminal prosthesis, such as
a stent, within a body lumen.
BACKGROUND OF THE INVENTION
[0003] An intraluminary prosthesis is a medical device used in the
treatment of diseased bodily lumens. One type of intraluminary
prosthesis used in the repair and/or treatment of diseases in
various body lumens is a stent. A stent is generally a longitudinal
tubular device formed of biocompatible material, which is useful to
open and support various lumens in the body. For example, stents
may be used in bodily vessels, such as in the coronary or
peripheral vasculature, esophagus, trachea, bronchi colon, biliary
tract, urinary tract, prostate, brain, as well as in a variety of
other applications in the body. These devices are implanted within
the vessel to open and/or reinforce collapsing or partially
occluded sections of the lumen. While stents and other
intraluminary prosthesis are foreign objects to the human body,
they are designed to remain within a body lumen for prolonged
periods or even indefinitely.
[0004] Stents generally include an open flexible configuration.
This configuration allows the stent to be inserted through curved
vessels. Furthermore, this configuration allows the stent to be
configured in a radially compressed state for intraluminary
catheter implantation. Once properly positioned adjacent the
damaged vessel, the stent is radially expanded so as to support and
reinforce the vessel. Radial expansion of the stent may be
accomplished by inflation of a balloon attached to the catheter or
the stent may be of the self-expanding variety which will radially
expand once deployed. Tubular shaped structures, which have been
used as intraluminary vascular stents, have included helically
wound coils which may have undulations or zigzags therein, slotted
stents, ring stents, braided stents and open mesh wire/filament
stents, to name a few. Super-elastic materials and metallic shape
memory materials have also been used to form stents.
[0005] On occasion there is a need to retrieve or reposition a
stent previously deployed in a body lumen. For example, a stent may
require repositioning if incorrectly located during deployment, or
if it migrates after deployment. Also, the need to retrieve or
remove a deployed stent may arise from a post-deployment
determination that the stent was not the appropriate size for the
application, or from a procedure that calls for only temporary use
of the stent.
[0006] One known approach to removing a previously deployed stent
or other prosthesis involves capturing a proximal end of the object
with biopsy forceps or other snare, then pulling proximally to
withdraw the object. One problem with this approach is that pulling
or pushing a fully radially expanded stent through a body lumen can
damage surrounding tissue and the stent itself.
[0007] Therefore, there is a need for a reliable and effective
apparatus, system and method for removing, adjusting and/or
repositioning an intraluminary prosthesis that has already been
deployed, which overcomes the shortcomings set forth above while
also having application to other select intraluminary objects.
SUMMARY OF THE INVENTION
[0008] The present invention is directed to an apparatus, system
and method for moving an object disposed within a body lumen. In
particular, the present invention relates to an apparatus and
method for using the apparatus for retrieving, adjusting and/or
repositioning an intraluminary prosthesis, such as a stent.
[0009] In one embodiment of the present invention an apparatus for
moving an object disposed within a body lumen includes a first
sheath for insertion into the body lumen, a coupling member and at
least one contraction member for engaging at least a portion of the
object. The coupling member is movable relative to the first sheath
between a retracted position and a capture position. In the
retracted position, a distal portion of the coupling member is
disposed within the first sheath. In the capture position, the
coupling member distal portion is disposed outside the first
sheath. The coupling member is also selectively attachable to the
object in at least the capture position. When the coupling member
is attached to the object and the contraction member is directly
engaged with the object, a predetermined coupling member movement
relative to the contraction member radially contracts at least a
portion of the object thereby facilitating movement of the object
within the body lumen.
[0010] Additionally, the coupling member and the contraction member
of the apparatus can cooperate to draw the object at least
partially within the first sheath. Also, the coupling member can
include at least one first grasping member for removeably attaching
to the object, wherein the first grasping member includes at least
one of a hook, forceps, clamp and snare. The contraction member can
include a deployable funnel with an inner passage for receiving the
object, with at least one portion of the funnel being selectively
adjustable between a radially compressed and a radially expanded
configuration. Further, another predetermined coupling member
movement relative to the funnel can encourage the funnel to adjust
to the expanded configuration. Also, the coupling member can be
axially moveable relative to the funnel and the funnel can be
axially moveable relative to the first sheath. Further, at least a
distal portion of the coupling member can be disposed within the
inner passage when the coupling member is in the retracted
position. Further still, the coupling member can include at least
one stop member for limiting axial movement of the coupling member
relative to the funnel. Yet further still, the coupling member can
include a cap, whereby the cap retains the funnel in the compressed
configuration. Yet further still, the funnel can be disposed at a
distal end of the first sheath and/or integrally formed with the
first sheath.
[0011] Also, the contraction member can include a second sheath
moveably disposed with respect to the first sheath, wherein at
least a portion of the second sheath is coaxially disposed within
the first sheath. The coupling member can further include at least
one elongate rod extending generally parallel to the first sheath.
The first grasping member can be disposed on a distal end of the
rod. Also at least a portion of the rod can be biased to diverge
radially away from a central longitudinal axis of the sheath.
Additionally, at least one elongate rod can extend from a distal
end of the second sheath. The rod can extend generally parallel to
at least one of the first and second sheath, wherein at least a
distal portion of the rod can be disposed outside the first sheath
when the contraction member is in the capture position. Further the
contraction member can include at least one second grasping member
for removeably attaching to the object, whereby the first and
second grasping members can cooperate to radially contract the
object. Additionally, when in the capture position the first
grasping member can secure to a distal portion of the object and
the second grasping member can secure to a proximal portion of the
object.
[0012] In another embodiment of the present invention a method for
moving an intraluminary object disposed within a body includes
providing a first sheath for insertion into a body lumen, a
coupling member and at least one contraction member for engaging at
least a portion of the object. The coupling member is movable
relative to the first sheath between a retracted position wherein a
distal portion of the coupling member is disposed within the first
sheath and a capture position wherein the coupling member distal
portion is disposed outside the first sheath. The coupling member
is selectively attachable to the object in at least the capture
position. Also, when the coupling member is attached to the object,
a predetermined coupling member movement relative to the
contraction member radially contracts at least a portion of the
object thereby facilitating movement of the object within the body
lumen.
[0013] Additionally, the method can further include inserting the
first sheath, the coupling member and the contraction member into
the body lumen with at least the coupling member in a retracted
position. Also, the method can further include moving the coupling
member into the capture position and attaching the coupling member
to the object. Further, the predetermined coupling member movement
can be initiated in order to move the object relative to the body
lumen. Also, the coupling member and the contraction member of the
method can cooperate to draw the object at least partially within
the first sheath. Further, the coupling member of the method can
includes at least one grasping member for removeably attaching to
the object. The grasping member can include at least one of a hook,
forceps, clamp and snare. Also, the coupling member can include at
least one elongate rod extending generally parallel to the first
sheath. The grasping member of the method can be disposed on a
distal end of the rod. Also, the predetermined coupling member
movement can include a distal portion of the coupling member moving
at least one of toward and away from a distal portion of the
contraction member. Further, the radial contraction of the object
can be associated with at least one of an elongation of the object
and extrusion of the object through the contraction member.
[0014] These and other objectives, features, and advantages of this
invention will become apparent from the following detailed
description of illustrative embodiments thereof, which is to be
read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 illustrates a perspective view of an embodiment of
the apparatus for moving an intraluminal prosthesis in accordance
with the subject invention.
[0016] FIG. 2 illustrates a plan view of a distal portion of the
apparatus of FIG. 1 in cross-section disposed within a body lumen
adjacent an intraluminal prosthesis.
[0017] FIGS. 3-5 illustrate sequential plan views in cross-section
of the apparatus of FIGS. 1 and 2 moving to capture and move the
intraluminal prosthesis.
[0018] FIG. 6 illustrates a plan view of a distal portion in
cross-section of an alternative embodiment of the apparatus in
accordance with the subject invention adjacent an intraluminal
prosthesis.
[0019] FIGS. 7-9 illustrate sequential plan views in cross-section
of the apparatus of FIG. 6 moving to capture and move the
intraluminal prosthesis.
[0020] FIG. 10 illustrates a plan view in cross-section of a distal
portion of another alternative embodiment of the apparatus in
accordance with the subject invention.
[0021] FIG. 11 illustrates a perspective view of the apparatus of
FIG. 10 removeably attached to an intraluminal prosthesis.
[0022] FIGS. 12-14 illustrate sequential perspective views of the
apparatus of FIGS. 10 and 11 actuated to radially contract the
intraluminal prosthesis.
[0023] FIGS. 15a and 15b illustrate an alternative embodiment of
the grasping members in accordance with the subject invention.
[0024] FIGS. 16 and 17 illustrate further alternative embodiments
of the grasping members in accordance with the subject
invention.
[0025] FIG. 18 illustrates a perspective view of a yet another
alternative embodiment of the apparatus in accordance with the
subject invention.
[0026] FIG. 19 illustrates a plan view of a distal portion of the
apparatus of FIG. 18 in cross-section disposed within an
intraluminal prosthesis.
[0027] FIGS. 20-22 illustrate sequential plan views in
cross-section of the apparatus of FIGS. 18 and 19 moving to capture
and radially contract the intraluminal prosthesis.
DETAILED DESCRIPTION OF THE INVENTION
[0028] The present invention relates to an apparatus, system and
method for moving an object disposed in a bodily passageway. The
invention allows the clinician or operator to remove or adjust the
position of the object while minimizing damage to the object itself
and the surrounding tissue. The assembly is preferably suited for
medical applications (particularly, endoscopic therapy) in the
gastrointestinal tract, the biliary tract, the urinary tract, and
the respiratory tract. In particular, a preferred embodiment of the
present invention is directed to an assembly, system and method for
retrieving, adjusting and/or repositioning an intraluminary
prosthesis, such as a stent in a biliary duct. Additionally, an
assembly in accordance with the present invention could be used in
the neurological system (e.g., in the brain) and in the
cardiovascular system (e.g., in the heart). Reference herein to
bodily passageways or lumens may be to vessels or passageways in
any of the aforementioned tracts and systems or elsewhere in the
body. While discussed below primarily in connection with retrieving
radially self-expanding stents, the apparatus and systems of the
present invention can also be used to recover or reposition other
types of stents and prostheses (e.g., stent-grafts). Additionally,
in accordance with the present invention the assembly could also be
used to remove other objects from within a body lumen.
[0029] It should be noted that references herein to the term
"distal" are to a direction away from an operator of the subject
invention, while references to the term "proximal" are to a
direction towards the operator of the subject invention.
Accordingly, when the terms "distal" and "proximal" are used herein
in the context of an assembly device that is being deployed within
a body, such as a human body, by an operator, the term "distal"
refers to a location within the body that is further within the
body than a location that is "proximal" to the operator.
[0030] With reference to the drawings, FIG. 1 shows an apparatus
100 for moving an object, such as a stent, disposed within a
passageway or body lumen. The apparatus 100 is preferably used for
retrieving, adjusting and/or repositioning a radially contractible
stent or other prosthesis previously deployed in a body lumen.
Apparatus 100 includes a sheath member 120, at least one
contraction member 140 and a coupling member 160. In FIG. 1, the
apparatus 100 is shown in an extended or deployed position.
However, contraction member 140 and coupling member 160 can
preferably be retracted so they are substantially disposed inside
sheath 120. In this way, the retracted configuration of apparatus
100 can have the narrower profile of sheath 120 and can be more
easily inserted into and navigated within a body lumen. Once
positioned in a desired location/configuration within a body lumen,
contraction member 140 and coupling member 160 can be axially
deployed from inside sheath 120. It should be noted that the
apparatus 100, or portions thereof, can be used as part of or in
conjunction with other endoscopic systems.
[0031] FIGS. 2-5 illustrate the apparatus 100 inserted in a body
lumen 10 in various stages of deploying and attaching to stent 20.
The elongate pliable sheath 120 preferably has a handle 121 at its
proximal end to facilitate manipulation of the sheath. At its
distal end 128 the sheath 120 includes an aperture 129 for
deploying the inner elements. Sheath 120 is preferably designed for
entry into the body, and transluminal travel to a selected site in
a body lumen 10. To this end, the sheath is pliable in the sense
that it readily bends to accommodate curved or serpentine luminal
passages, yet has sufficient axial stiffness to allow control of
the transluminal travel from the proximal end of the sheath. A
sheath lumen 125 runs longitudinally through the sheath 120.
[0032] Sheath 120 is preferably formed of a body compatible
material. Desirably, the biocompatible material is a biocompatible
polymer. Examples of suitable biocompatible polymers include, but
are not limited to, polypropylene (PP), polytetrafluoroethylene
(PTFE), polyethylene terephthalate (PET), high density polyethylene
(HDPE) and the like. Additionally, the sheath 120 could have
layers, coverings, films, coatings, and the like, desirably a
polymeric covering, disposed over the outer or inner surfaces to
improve interaction with the body lumen and the inner elements
discussed below. Further, the sheath 120 or select portions thereof
could be clear, opaque, translucent, colored and/or non-transparent
as desired.
[0033] FIGS. 1-5 also illustrate an embodiment of the contraction
member 140 in accordance with the present invention. Preferably,
contraction member 140 forms a distally diverging or expanding cone
or funnel. The funnel 140 is preferably formed of an elastic
material that can be compressed to fit inside sheath 120 and will
expand once no longer radially constricted. In this way, it can be
axially moved beyond the distal end 128 of sheath 120, thus
allowing at least a distal portion 148 of the funnel 140 to expand
and diverge from the narrower collar portion 142, forming a
funnel-shaped element. An inner passage 145 of the funnel 140 is
adapted to receive at least a portion of the select object disposed
within a body lumen intended for movement.
[0034] The funnel 140 is preferably formed of a material or
materials can radially expand and provide sufficient stiffness to
act as a funneling member for a prosthesis pulled through its inner
passage 145. The funnel 140 can be formed of materials similar to
those used for contemporary self-expanding stents. Thus, the funnel
140 can be formed of metals, plastics or other materials, however
it is preferred that a biocompatible construction is employed.
Useful biocompatible materials include but are not limited to
biocompatible metals, biocompatible alloys, biocompatible polymeric
materials, including synthetic biocompatible polymeric materials
and bioabsorbable or biodegradable polymeric materials, materials
made from or derived from natural sources and combinations thereof.
Useful biocompatible metals or alloys include, but not limited to,
nitinol, stainless steel, cobalt-based alloy such as Elgiloy,
platinum, gold, titanium, tantalum, niobium, polymeric materials
and combinations thereof. Useful synthetic biocompatible polymeric
materials include, but are not limited to, polyesters, including
polyethylene terephthalate (PET) polyesters, polypropylenes,
polyethylenes, polyurethanes, polyolefins, polyvinyls,
polymethylacetates, polyamides, naphthalane dicarboxylene
derivatives, silks and polytetrafluoroethylenes. The polymeric
materials may further include a metallic, a glass, ceramic or
carbon constituent or fiber. Useful and nonlimiting examples of
bioabsorbable or biodegradable polymeric materials include
poly(L-lactide) (PLLA), poly(D,L-lactide) (PLA), poly(glycolide)
(PGA), poly(L-lactide-co-D,L-lactide) (PLLA/PLA),
poly(L-lactide-co-glycolide) (PLLA/PGA),
poly(D,L-lactide-co-glycolide) (PLA/PGA),
poly(glycolide-co-trimethylene carbonate) (PGA/PTMC), polydioxanone
(PDS), Polycaprolactone (PCL), polyhydroxybutyrate (PHBT),
poly(phosphazene) poly(D,L-lactide-co-caprolactone) PLA/PCL),
poly(glycolide-co-caprolactone) (PGA/PCL), poly(phosphate ester)
and the like. Further, the funnel 140 may include materials made
from or derived from natural sources, such as, but not limited to
collagen, elastin, glycosaminoglycan, fibronectin and laminin,
keratin, alginate, combinations thereof and the like.
[0035] Also, it should be understood that the materials of the
funnel 140 as well as the component filaments of the funnel 140 can
be further enhanced with coverings, films, coatings, and other
materials and techniques. A covering may be composed of polymeric
material and/or silicone. The covering may also comprise any
plastic or polymeric material, desirably a somewhat hard but
flexible plastic or polymeric material. The covering may be
transparent or translucent, desirably substantially or partially
transparent. Furthermore, the covering may be constructed of any
suitable biocompatible materials, such as, but not limited to,
polymers and polymeric materials, including fillers such as metals,
carbon fibers, glass fibers or ceramics. Useful covering materials
include, but are not limited, polyethylene, polypropylene,
polyvinyl chloride, polytetrafluoroethylene, including expanded
polytetrafluoroethylene (ePTFE), fluorinated ethylene propylene,
fluorinated ethylene propylene, polyvinyl acetate, polystyrene,
poly(ethylene terephthalate), naphthalene dicarboxylate
derivatives, such as polyethylene naphthalate, polybutylene
naphthalate, polytrimethylene naphthalate and trimethylenediol
naphthalate, polyurethane, polyurea, silicone rubbers, polyamides,
polyimides, polycarbonates, polyaldehydes, polyether ether ketone,
natural rubbers, polyester copolymers, styrene-butadiene
copolymers, polyethers, such as fully or partially halogenated
polyethers, and copolymers and combinations thereof. The coating or
coatings may be on the entire funnel 140 or portions thereof.
[0036] Preferably, the funnel 140 includes a narrowed collar
portion 142 on its proximal end providing a sliding mounted
engagement with control rod 162. The collar portion 142 is
preferably banded or permanently restricted in some way from radial
expansion. The collar portion 142 should be suitably sized to allow
relative axial movement between funnel 140 and control rod 162.
However, such axial movement is preferably limited to movement
between two spaced apart stop members 141, 149. Thus, the inner
diameter of the collar portion 142 should not exceed the outer
diameter of stop members 141, 149 in order to ensure the
appropriate limited relative axial movement. Also, funnel 140 and
control rod 162 are both preferably axial moveable relative to
sheath 120.
[0037] The stop members 141, 149 are preferably secured to rod 162
for limiting relative movement between the rod 162 and the funnel
140. While stop members 141, 149 are illustrated as radial bands or
sleeves secured to rod 162, they could alternatively comprise a
small radial protrusion on a portion of rod 162, sufficient to
limit funnel collar 142 axial movement. In a further alternative
embodiment, the stop members 141, 149 can be the end walls of a
longitudinal channel formed in rod 162, with funnel 140 including a
pin designed for guided movement within that channel.
[0038] The coupling member 160 includes an elongate pliable tube or
control rod 162, a rod handle 161 and at least one capture or
grasping member 165 for attaching to a stent or other object. The
coupling member 160 is coaxially disposed with and axially moveable
relative to the sheath 120. However, it should be understood that
locking elements (not shown) could be provided to adjustably fix
the relative position of the sheath 120 and coupling member 160 as
desired. Also, preferably located at the distal end 168 of control
rod 162 is the grasping member 165. The control rod 162 is also
preferably made of one of the biocompatible materials mentioned
above with regard to the sheath 120. However, the control rod 162
could be made of the same or a different material as the sheath
120.
[0039] Grasping member 165 is used to grab or attach itself to an
intraluminary prosthesis, such as a stent. Preferably, grasping
member 165 is formed like forceps with a pair of clamping surfaces
or jaws (with or without serrations) mounted to pivot relative to
the control rod 162 about a transverse axis. It should be
understood, however, that grasping member 165 could alternatively
be formed as a hook or snare as illustrated in the later
embodiments discussed below. The jaw pivoting style grasping member
165 is preferably controlled through one or more wires, sutures or
filaments (not shown). The wires are coupled to grasping member 165
and extend through one or more lumens in the control rod 162 to a
control handle 161 disposed at or near the proximal end of the
control rod 162.
[0040] The rod handle 161 is preferably provided with manipulating
features 163, 164 for controlling the position, configuration and
orientation of the grasping member 165. Also, preferably the
proximal manipulating feature 163 is moveable relative to the
adjacent manipulating feature 164 in order to open and close
grasping member 165 as desired. Feature 163 can be pulled axially
away from feature 164 in order to open grasping member 165.
Alternatively, the relative movement between features 163, 164
could be rotational or some other movement which would actuate
grasping member 165. Also, preferably feature 163 is axially biased
through a spring-type mechanism (not shown), encouraging it to
return to a position which closes grasping member 165. Such a
spring-type mechanism could be located in the rod handle 161.
[0041] FIGS. 2-5 illustrate the use of apparatus 100 to retrieve,
adjust and/or reposition an intraluminally deployed stent 20. When
initially advanced to the site of a deployed stent 20, the
apparatus 100 is preferably fully or at least substantially
retracted, with the funnel 140 fully contained within sheath 120.
Once the surgeon or operator is prepared to engage the target
object, the rod handle 161 can be moved in the distal direction,
while holding the sheath handle 121 stationary, toward a capture
position as illustrated in FIG. 2. Alternatively, the surgeon could
move the sheath handle 121 proximally, while holding the rod handle
161 stationary. Either way, the result of this relative axial
movement between members is that the sheath 120 is retracted from
covering at least the grasping member 165. The operator could find
advantage in deploying the grasping member 165, and not the funnel
140, in order to more freely position the device 165 and attach it
to the target object 20. This prevents the funnel 140 from
interfering with the effort to guide and/or position the grasping
member 165.
[0042] With the jaws of the grasping member 165 properly aligned
with the target object, the operator can then manipulate the
grasping member 165 to engage a portion thereof. Pulling
manipulating feature 163 proximally, while maintaining sheath
handle 121 and rod handle 161 in place, causes the clamping
surfaces to open, as illustrated in FIG. 3. Then by pushing or, if
biased, allowing manipulating feature 163 to return to its more
distal closed position the user can grasp or capture a portion of
the target object, as illustrated in FIG. 4. This task can be made
easier when the target object is a stent 20 that includes end
portions 22 that are not quite as fully radially expanded as the
rest of the stent. For example, many contemporary stents 20 include
end loops (as illustrated in FIG. 11) that, even in there fully
deployed configuration, tend to deflect radially inwardly slightly.
Thus, an operator might have an easier time snagging one of these
end loops or a similar deflecting end portions 22 with the grasping
member 165.
[0043] Once the grasping member 165 is attached to the stent 20,
the operator preferably moves sheath handle 121 toward the rod
handle 161 to further retract sheath 120 until funnel 140 is
deployed and expands to the open configuration, as illustrated in
FIG. 4. Although funnel 140 is slidingly mounted on control rod
162, stop member 141 will engage and push on the collar portion 142
of funnel 140, causing the funnel 140 to deploy. Thereafter, the
stent 20 can be pulled toward the sheath 120, by holding sheath
handle 121 in place and moving rod handle 161 proximally. It should
be noted that due to a relatively low-friction mounting of funnel
collar 142 about the control rod 162, funnel 140 will generally not
immediately enter the distal aperture 128 of sheath 120. During at
least the initial retraction of grasping member 165 and control rod
162, the funnel 140 will tend to slide along rod 162 until collar
142 abuts stop member 149, as illustrated in FIG. 4. Once stop
member 149 engages funnel collar 142, the funnel 140 can be pulled
back into sheath 120. Additionally, it should be noted that once
stop member 149 and funnel collar 142 are engaged, the grasping
member 165, along with at least the attached portion of the stent
20, should be disposed within the inner funnel passage 145.
Thereafter, further pulling the rod handle 161 proximally away from
sheath handle 121 draws funnel 140, grasping member 165 and at
least the attached portion of the stent 20 into the outer sheath
120 as illustrated in FIG. 5.
[0044] Preferably, during the final phases of retraction the funnel
140 radially compresses a proximal portion of stent 20 and guides
it into the sheath 120. As the funnel 140 is drawn back into the
sheath 120, it is radially compressed by the sheath 120 and in turn
radially compresses at least a proximal portion of the stent 20.
Once at least a proximal portion of the stent 20 is drawn into the
sheath 120, it can more easily be moved proximally within the body
lumen 10. The stent 20 could also be fully drawn into sheath 120
for complete removal from the body lumen 10. Also, even if the
stent 20 is not easily radially compressible, if at least the edge
portion 22 can be drawn into funnel channel 145, the preferably
low-friction outer surface of funnel 140 can more gently guide the
leading edge of the stent 20 as it is being pulled through the body
lumen 10. Further, if stent 20 is a self-expanding stent, distal
repositioning can be achieved by retracting the entire stent 20
into sheath 120. Once the stent 20 is loaded in apparatus 100, the
loaded assembly can be moved distally to the target repositioning
location. Then the sheath 120 can be retracted and grasping member
165 opened, thereby releasing and redeploying the stent 20.
[0045] FIGS. 6-9 illustrate an alternative embodiment of the
apparatus of the present invention. The distal end of an apparatus
200 is shown, along with a stent 20. The apparatus 200 includes a
sheath member 220, at least one contraction member 240 and a
coupling member 260. It should be understood that although the
proximal end of this and some later embodiments is not shown, they
can have the same or similar designs to those illustrated in FIG. 1
or 18, or other similar assemblies known in the field of
endoscopy.
[0046] Apparatus 200 preferably includes an elongate pliable sheath
220 having the same or similar construction and/or composition as
that of sheath 120 described above. A lumen 225 preferably extends
axially along the length of sheath 220. Additionally, a distal end
region 224 of sheath 220 is designed to radially expand or flare
when unrestrained or otherwise actuated to do so.
[0047] As illustrated in FIGS. 7-9, the radially expanded end
region 224 forms a contraction member or funnel 240. Thus, funnel
240 includes a conical inner passage 245 intended for receiving a
targeted intraluminary object. Although end region 224 is
illustrated as being formed of the same material as the rest of
sheath 220, it could be formed from a more flexible self-expanding
material, such as those described for funnel 140 above.
Nonetheless, funnel 240 is preferably either integrally formed with
or fixedly secured to the rest of sheath 220.
[0048] Coupling member 260 includes an elongate pliable control rod
262, which preferably extends coaxially with sheath 220. Control
rod 262 is axially moveable relative to the sheath 220, similar to
the relationship between rod 162 and sheath 120 discussed above.
Preferably, coupling member 260 includes an inner lumen 263, which
extends therethrough. Lumen 263 can be used as a flush port, guide
wire channel or other suitable access to a desired bodily
passageway. The distal end of rod 262 includes a head 268 that
preferably narrows and converges in the distal direction. As
illustrated in FIG. 6, the head 268 acts as the leading distal edge
for the overall apparatus 200 when it is being inserted into body
cavities and lumens. Thus, the converging head 268 can assist in
navigating through narrow passageways within the body. The head 268
can be formed of the same material as the rod 262, as illustrated,
or it could be formed from another material. In fact, head 268
could be formed to provide a more or less rigid composition than
that of flexible rod 262. However, it is preferable that head 268
be either integrally formed with or fixedly secured to rod 262.
[0049] Additionally, a proximal portion of the head 268 is
preferably formed as a proximally protruding sleeve or annular
flange 267. As illustrated in FIG. 6, the flange 267 is sized to
fit over, in concentric fashion, and restrain end region 224 from
radially expanding. However, once coupling member is moved distally
relative to the sheath 220 and flange 267 is no longer engaged with
end region 224, radial expansion occurs and funnel 240 is thus
deployed.
[0050] Coupling member 260 also includes grasping member 265.
Preferably, grasping member 265 includes one or more radially
protruding hooks, barbs or snares designed to catch and hold an end
portion 22 of stent 20. The grasping member 265 is preferably
self-expanding, so it can be deployed from a radially compressed
state when contained within sheath lumen 225 to a radially expanded
state as illustrated in FIGS. 7 and 8.
[0051] FIGS. 6-9 together illustrate a sequence for using apparatus
200 to retrieve a previously deployed stent 20. Initially,
apparatus 200 is intraluminally inserted and advanced to the region
immediately adjacent to where the stent 20 is located, as
illustrated in FIG. 6. As shown, during that initial insertion
stage, control member 260 is preferably maintained in a proximal or
retracted position with respect to sheath 220. Then, while holding
the sheath 220 relatively still, the control member 260 is advanced
distally until the grasping members 265 are surrounded by at least
the proximal end portions 22 of the stent 20, as illustrated in
FIG. 7. At this point, both the funnel 240 and grasping members 265
are preferably deployed as shown. Thereafter, the control member
260 is retracted in order to engage and snare or attach one or more
of the grasping members 265 with the stent 20, as illustrated in
FIG. 8. Then by holding sheath 220 steady and pulling control
member 260 further in the proximal direction relative to the sheath
220, at least the proximal portions of the stent 20 are made to
radially contract as they are pulled into the funnel 240, as
illustrated in FIG. 9. In this last configuration, with at least
the proximal end 22 of stent 20 constricted, it can more easily be
pulled proximally through the body lumen. As mentioned with regard
to the earlier embodiments, apparatus 200, or portions thereof, can
be used as part of or in conjunction with other endoscopic
systems.
[0052] Alternatively, the grasping members 265, in the form of
self-expanding radially extending hooks or snares, need not extend
from the rod 262. In this alternative, embodiment the flange 267
proximally extending from the head 268 of the coupling member 260
is used to catch the stent 20. By pulling the head 268 proximally
and trapping or pinching an end portion of the stent 22 between the
proximal edge of the flange 267 and the inner surface 245 of the
funnel 240, the apparatus 200 can be alternatively used to move an
intraluminary object. Thus, the proximal edge of the flange 267 can
also act as a grasping member. Also, rather than flange 267 being
formed as an annular sleeve, it can be formed as several elongate
fingers or tabs axially extending from the proximal peripheral edge
of head 268. Such tabs can then either clamp a portion of the stent
22 or snare an end loop of the stent 20, hooking and trapping it
between the tabs and the funnel 240.
[0053] In yet a further alternative embodiment of apparatus 200, a
relatively smaller head 268 is provided than that shown in FIG.
6-9. In this embodiment, preferably the smaller version of head 268
fits within sheath lumen 225, whereby the head 268 and the full
length of the stent are retracted into all or a portion of the
sheath 220.
[0054] FIGS. 10-14 illustrate a further alternative embodiment of
the apparatus of the present invention. In particular, the distal
end region of apparatus 300 is shown. Apparatus 300 includes a
sheath member 320, at least one contraction member 340 and a
coupling member 360. The sheath 320, contraction member 340 and
coupling member 360 are all concentrically configured as shown and
axially moveable relative to one another. In FIG. 10, the apparatus
300 is shown in a retracted and radially compressed configuration.
However, by moving contraction member 340 and coupling member 360
distally (toward the right as illustrated in FIG. 10) relative to
sheath 320, the distal portions of the inner members can be
extended beyond the distal end of the sheath 320 and thus outside
sheath lumen 325. Similarly, by moving coupling member 360 distally
relative to the contraction member 340, coupling member 360 will
extend beyond the distal end of contraction member 340 and thereby
radially expand, as described further below.
[0055] Contraction member 340 is preferably formed like the outer
sheath 320 in that it is an elongate flexible tube. However, while
contraction member 340 and sheath 320 can be formed of the same or
similar materials and/or finishes, they can be different if
desired. In contrast, coupling member 360 is formed from one or
more elongate wires 362 that extend through an inner lumen of
contraction member 340. The wires 362 are preferably formed of body
compatible materials, such as stainless steel, nitinol, ceramic or
polymer based materials. Also, as with the first embodiment, the
sheath 320, contraction member 340 and coupling member 360 are each
preferably coupled to handles (not shown) that control independent
movement of each member relative to the others.
[0056] As illustrated in FIG. 11, preferably coupling member 360 is
formed by three wires 362 that are fused together over most of the
length of the coupling member 360. Respective distal end segments
364 of the wires 362 include a bend 363 which causes the end
segments 364 to diverge distally when not constrained. Thus, the
distal end segments 364 of the wires 362 are preferably formed with
enough elasticity such that the bend 363 can be generally
straightened or the diverging segments 364 radially compressed
together when held within the contraction member 340, yet
self-expanding when deployed therefrom. Additionally, each of the
wires 362 respectively supports a grasping member 365 at their
distal end.
[0057] FIGS. 11-14 also illustrate the apparatus 300 engaged with a
stent 20. Preferably, the number of wires 362 and corresponding
grasping members 365 included in the apparatus 300 are chosen and
configured to correspond to attachable end segments of the stent
20. In this and the other embodiments, it is desirable that stent
20 be formed with an open weave or mesh construction; including
multiple helically wound filaments of a flexible body compatible
material, examples of which were recited above. The end portions 22
of the stent 20, or at least the proximal end, include(s) loops
which can provide a convenient segment for engagement by the
grasping members discussed herein. Alternatively, the end portions
22 can have a smaller loops or bends. Such bends or loops can be
formed by a pair of helical windings, the ends of which are curved
and either integrally formed or joined together. Such loops or
bends provide a convenient coupling point as described herein.
Also, such loops or bends are preferably designed to slightly
deflect radially inwardly when fully deployed to facilitate
engagement by a grasping member as described herein. Accordingly,
although a stent 20 when deployed tends to press radially outwardly
against surrounding tissue and to a certain extent becomes embedded
in that tissue, one or both end portions 22 preferably deflect
inwardly, remaining exposed and are readily accessible to the
grasping members in accordance with the invention.
[0058] FIGS. 11-14 together illustrate a sequence for using
apparatus 300 to engage and move a previously deployed stent 20. As
with the previous embodiments the apparatus 300 is transluminally
advanced in a retracted position to a site in a body lumen near to
where the stent 20 has been deployed. Thereafter, the contraction
member 340 and control member 360 are advanced further distally,
while holding the sheath 320 relatively stationary. In fact,
preferably contraction member 340 and control member 360 are
advanced together to a point, such that grasping members are
axially surrounded by the stent 20, but held in a radially
compressed configuration. Then the contraction member 340 is pulled
back proximally so that the end segments 364 of the control member
360 are allowed to radially expand and diverge from one another. By
delicately proximally pulling the apparatus 300, or at least the
control member 360, the grasping members 365 preferably snare
and/or trap one or more end portions 22 of the stent 20, as
illustrated in FIG. 11. Just prior to this capture phase, the
operator may be required to axially rotate portions of the
apparatus 300, namely control member 360, in order to align the
grasping members 365 with one or more end loops 22 of the stent 20,
as shown.
[0059] With the coupling maintained between the stent 20 and the
grasping member 365, the distal end 348 of contraction member 340
is advanced distally relative to the control member 360, which
causes grasping members 365 to radially contract as the end
segments 364 enter the lumen of contraction member 340.
Alternatively, either the control member 360 can be pulled
proximally while holding the contraction member 340 relatively
still or both members 340, 360 can be moved to achieve the desired
radial inward movement of the grasping members 365. As grasping
members 365 are drawn together the end portions 22 of the stent 20
are also radially constricted, as illustrated in FIGS. 12 and
13.
[0060] As illustrated in FIG. 13, as the end segments 364 are
pulled inside contraction member 340, the grasping members are
eventually drawn close to one another along with the stent ends 22.
At this stage, the apparatus 300 or portions thereof can be pulled
proximally to reposition the stent 20. Thus, grasping members 365
are preferably configured to releasably engage the stent 20 for
release while still within the body lumen. Alternatively, as
illustrated in FIG. 14, the grasping members 365 can be further
drawn into the sheath 320, after which stent 20 repositioning can
be accomplished. It should be noted that as with previous
embodiments, such repositioning could include removal of the stent
20 from the body lumen or a repositioning and/or reconfiguration of
the stent within the body lumen. Also, the entire stent 20 could
potentially be drawn inside sheath 320. Additionally, a fully or
significantly radially constricted self-expanding stent 20 could
also potentially be distally repositioned using these techniques.
Further, as mentioned with regard to the earlier embodiments,
apparatus 300, or portions thereof, can be used as part of or in
conjunction with other endoscopic systems.
[0061] FIGS. 13 and 14 further illustrate the use of a radiopaque
marker 327, preferably disposed at or near the distal end 328 of
sheath 320. Marker 327 can assist the operator in visualizing the
relative position of the apparatus 300 with relation to the target
object. Such a marker 327 can be formed from radiopaque materials,
such as metallic-based powders or ceramic-based powders,
particulates or pastes which may be incorporated into the distal
sheath 328 material. For example, the radiopaque material may be
blended with the polymer composition from which the polymeric
filament is formed, and subsequently fashioned into a portion of
the sheath 320. Alternatively, the radiopaque material may be
applied to the surface of the sheath 320. Various radiopaque
materials and their salts and derivatives may be used including,
without limitation, bismuth, barium and its salts such as barium
sulfate, tantalum, tungsten, gold, platinum and titanium, to name a
few. Additional useful radiopaque materials may be found in U.S.
Pat. No. 6,626,936, which is herein incorporated by reference.
Metallic complexes useful as radiopaque materials are also
contemplated. The sheath 320 may be selectively made radiopaque in
desired areas or made be fully radiopaque. Further, the distal
portion 328 of the sheath 320 may have an inner core of tantalum,
gold, platinum, iridium or combination of thereof and an outer
member or layer of nitinol to provide a composite filament for
improved radiocapicity or visibility. Alternatively, the sheath 320
may also have improved external imaging under magnetic resonance
imaging (MRI) and/or ultrasonic visualization techniques. MRI is
produced by complex interactions of magnetic and radio frequency
fields. Materials for enhancing MRI visibility include, but are not
limited to, metal particles of gadolinium, iron, cobalt, nickel,
dysprosium, dysprosium oxide, platinum, palladium, cobalt based
alloys, iron based alloys, stainless steels, or other paramagnetic
or ferromagnetic metals, gadolinium salts, gadolinium complexes,
gadopentetate dimeglumine, compounds of copper, nickel, manganese,
chromium, dysprosium and gadolinium. To enhance the visibility
under ultrasonic visualization the sheath marker 327 of the present
invention may include ultrasound resonant material, such as but not
limited to gold.
[0062] FIGS. 15a, 15b, 16 and 17 illustrate further alternative
embodiments for the grasping members 375, 385, 395 of the present
invention. In particular, FIGS. 15a and 15b respectively show an
open and closed position for a grasping member 375 that is formed
by a loop 374 and locking hook 376. This grasping member 375 can be
designed with locking hook 376 having an outward bias, but
configured to stay closed once caught on the edge of loop 374.
Alternatively, the upper hook 376 and lower loop 374 can be
designed to be actuated similar to the upper and lower portions of
grasping member 165 discussed above. In FIGS. 16 and 17 the
grasping members 385, 395 respectively include a lower hook 384,
394 and upper flap 386, 396. The grasping member 385 has an end
portion of its flap 386 disposed on top or outside the hook 384 and
can preferably be used for capturing a portion of a stent with a
forward or distal movement of the member 385. In contrast, grasping
member 395 has its flap 396 terminating inside the hook 394 and is
more likely used for a backward or proximal movement of the member
395 to capture a portion of a stent 20.
[0063] FIGS. 18-22 illustrate a further alternative embodiment of
the apparatus of the present invention. In particular, FIG. 18
shows apparatus 400, which includes a sheath member 420, a
contraction member 440 and a coupling member 460. The apparatus 400
in FIG. 18 is shown in an extended or deployed position. However,
contraction member 440 and coupling member 460 can preferably be
retracted so they are substantially disposed inside sheath 420. In
this way as with the earlier embodiments, the retracted
configuration of apparatus 400 can have a narrow profile and can be
more easily navigated through the body. Once positioned in a
desired location/configuration within a body lumen, contraction
member 440 and coupling member 460 can be axially deployed from
inside sheath 420.
[0064] The contraction member 440 and the coupling member 460 both
coaxially extend through and are axially moveable with respect to
an inner lumen of sheath 420. As with previous embodiments, the
sheath 420, contraction member 440 and coupling member 460 each
preferably include proximal handles 421, 441, 461 respectively for
controlling the position and configuration of each member relative
to the others. It should be understood that locking and/or
retaining elements (not shown) can be included which can
selectively and temporarily hold each handle 421, 441, 461 relative
to the other(s).
[0065] The contraction member 440 is preferably formed as a sheath
or rod with a lumen extending from end-to-end. Preferably, the
proximal end of contraction member 440 includes a contraction
handle 441 and the distal end includes axially extending strands or
wires 442. A grasping member 445 is preferably formed at the distal
end of each strand 442. It is preferred that the apparatus 400
include at least two contraction wires 442 in order to engage two
circumferentially spaced portions of the targeted object. However,
a greater or lesser number of wires 442 could be included. Also,
similar to wires 362, the wires 442 are either secured or formed in
such a way as to radially diverge from one another when
unrestrained.
[0066] The coupling member 460 is preferably similarly formed as a
rod extending through and axially moveable with respect to the
inner lumen of contraction member 440. While the greater length of
coupling member 460 is preferably formed as a solid rod, it could
be formed with a continuous inner lumen like the contraction member
400. Nonetheless, the coupling member 460 preferably includes a
coupling handle 461 on the proximal end and strands or wires 462
axially extending from the distal end thereof. Preferably, the
number of coupling wires 462 coincides with the number of
contraction wires 442, however a fewer or greater number of wires
462 can be provided. Preferably, the number and configuration of
contraction wires 442 and coupling wires 462 conforms to the number
and configuration of the end loops or bends to be engaged on the
target stent 20. Additionally, the coupling member 460 includes a
grasping member 465 at the distal end of each wire 462. The wires,
442, 462 can be formed from the same or similar materials to those
described above with respect to the wires 362 of apparatus 300
above. Also, similar to wires 362, 442, the wires 462 are either
secured or formed in such a way as to radially diverge from one
another when unrestrained. However, when in a retracted
configuration, the sheath 420 radially constricts both wires 442,
462 and their respective grasping members 445, 465 as illustrated
in FIG. 19. In this way, the elastic self-expanding wires 442, 462
deflect radially outwardly when the sheath 420 is pulled-back
proximally, as illustrated in FIG. 20.
[0067] FIGS. 19-22 illustrate a sequence for using apparatus 400 to
engage and radially contract stent 20. This embodiment is
particularly suited for use on stents 20 designed to radially
constrict when they are pulled or stretched longitudinally. The two
sets of grasping members 445, 465 are preferably formed from one or
more bends or hooks in the distal ends of the respective wires 442,
462. The contraction grasping member 445 and the coupling grasping
member 465 are formed to engage and removeably capture respectively
proximal and distal portions 22 of the stent 20. Thus, contraction
grasping members 445 are preferably formed with an inner portion of
its curve or hook facing proximally. In contrast, coupling grasping
members 465 are formed with an inner curve facing generally
distally, as shown.
[0068] As with the previous embodiments, the apparatus 400 is
transluminally advanced in a retracted position to a site in a body
lumen where the stent 20 has been deployed. In contrast to the
previous embodiments, the distal portion of the entire retracted
apparatus 400, including the sheath 420, is preferably advanced to
a point where it is axially surrounded by the stent 20 before the
sheath 420 is retracted. This initial position should have both
sets of grasping members 445, 465 also located inside the stent 20,
as illustrated by FIG. 19.
[0069] Next, the sheath 420 can be retracted by pulling the handle
421 proximally, while holding the other handles 441, 461 relatively
still. By pulling back the sheath 420, the unrestrained contraction
wires 442 and control wires 462 radially deflect and diverge
bringing the grasping members 445, 465 in close proximity to the
stent 20, as illustrated by FIG. 20.
[0070] Thereafter, the operator can bring the sets of grasping
members 445, 465 into engagement with the end portions 22 of the
stent 20, as illustrated by FIG. 21. While both sets 445, 465 can
be brought into engagement simultaneously, it may be easier for the
operator to engage one set at a time. Thus, by delicately
proximally pulling the contraction handle 441, while holding the
coupling handle 461 relatively still the operator can engage one or
more contraction grasping members 445 with the proximal stent end
portion 22. Similarly, by delicately distally pushing the control
handle 461, while holding the contraction handle 441 relatively
still the operator can engage one or more control grasping members
465 with the distal stent end portion 22.
[0071] Once the grasping members 445, 465 are appropriately engaged
with the stent 20, the operator moves handles 441, 461 relative to
one another in order to further separate the proximal and distal
grasping members 445, 465. This further separation pulls and
stretches the stent 20, as illustrated in FIG. 22. The apparatus
400 takes advantage of the fact that longitudinal stretching of
many stents 20, such as self-expanding stents, will generally cause
them to radially constrict or reducing their overall outer
diameter. Also, reducing the other diameter of the stent 20 tends
to separate it from the surrounding tissue from which it may have
been imbedded. Further, as the stent 20 constricts it will in turn
radially constrict the position of the grasping members 445, 465
and the corresponding distal segments of the contraction and
control wires 442, 462. Thus, the outer diameter of the stent 20
and the distal portions of the apparatus 400 are now configured in
a narrow profile that can be more easily moved within a body lumen.
Such movement can be distal, proximal and/or axially rotational
movement. Additionally, the narrow profile is preferably such that
the entire stent 20 or portions thereof can be easily pulled inside
the sheath 420. Once inside the sheath, the stent 20 can then be
moved and redeployed or removed entirely.
[0072] It should be understood that many of the elements from the
various embodiments described above are interchangeable. For
example, the grasping members 165 of apparatus 100 can be formed
more like the grasping member 265, 365, 375, 385, 395, 465 of the
other embodiments. Also, all the grasping members in any one
embodiment do not need to be the same.
[0073] While various embodiments of the present invention are
specifically illustrated and/or described herein, it will be
appreciated that modifications and variations of the present
invention may be effected by those skilled in the art without
departing from the spirit and intended scope of the invention.
* * * * *